Question: Who ruled the country known for its populations of Muslims, and the people who traded slaves into the Middle East, before it was conquered by the followers of Muhammad?
Context: Document 1: Guinea-Bissau: Guinea-Bissau was once part of the kingdom of Gabu, part of the Mali Empire; parts of this kingdom persisted until the 18th century. Other parts of the territory in the current country were considered by the Portuguese as part of their empire. Portuguese Guinea was known as the Slave Coast, as it was a major area for the exportation of African slaves by Europeans to the western hemisphere. Previously slaves had been traded by Arabs north to the northern part of Africa and into the Middle East.
Document 2: Syria: Sunni Muslims make up between 69–74% of Syria's population and Sunni Arabs account for 59–60% of the population. Most Kurds (8.5%) and most Turkoman (3%) are Sunni and account for the difference between Sunnis and Sunni Arabs, while 13% of Syrians are Shia Muslims (particularly Alawite, Twelvers, and Ismailis but there are also Arabs, Kurds and Turkoman), 10% Christian (the majority are Antiochian Greek Orthodox, the rest are Syrian Orthodox, Greek Catholic and other Catholic Rites, Assyrian Church of the East, Armenian Orthodox, Protestants and other denominations), and 3% Druze. Druze number around 500,000, and concentrate mainly in the southern area of Jabal al-Druze.President Bashar al-Assad's family is Alawite and Alawites dominate the government of Syria and hold key military positions. In May 2013, SOHR stated that out of 94,000 killed during the Syrian Civil War, at least 41,000 were Alawites.Christians (2.5 million), a sizable number of whom are found among Syria's population of Palestinian refugees, are divided into several sects: Chalcedonian Antiochian Orthodox make up 45.7% of the Christian population; the Catholics (Melkite, Armenian Catholic, Syriac Catholic, Maronite, Chaldean Catholic and Latin) make up 16.2%; the Armenian Apostolic Church 10.9%, the Syriac Orthodox make up 22.4%; Assyrian Church of the East and several smaller Christian denominations account for the remainder. Many Christian monasteries also exist. Many Christian Syrians belong to a high socio-economic class.
Document 3: Umayyad Caliphate: The Quran and Muhammad talked about racial equality and justice as in The Farewell Sermon. Tribal and nationalistic differences were discouraged. But after Muhammad's passing, the old tribal differences between the Arabs started to resurface. Following the Roman–Persian Wars and the Byzantine–Sassanid Wars, deep rooted differences between Iraq, formally under the Persian Sassanid Empire, and Syria, formally under the Byzantine Empire, also existed. Each wanted the capital of the newly established Islamic State to be in their area. Previously, the second caliph Umar was very firm on the governors and his spies kept an eye on them. If he felt that a governor or a commander was becoming attracted to wealth, he had him removed from his position.
Answer: Byzantine Empire
Reasoning steps: Who traded slaves into the Middle East? Answer: Arabs
What country is known for its Arabs and Muslims? Answer: Syria
Who ruled Syria before it was conquered by the followers of Muhammad? Answer: Byzantine Empire